1. Field of the Invention
The present invention relates generally to a coin return protection device and, more particularly, to a device which can be attached to existing payphone coin return doors to prevent tampering with the coin return mechanisms.
2. Description of the Prior Art
The payphone coin return mechanisms in use today typically comprise a hollow body having front and back walls and top and bottom walls which are joined by opposing side walls. An intermediate wall is situated between the top and bottom walls and extends from a point below the back of the top wall downwardly toward the front wall to define with the top wall and the side walls a throat for the coin return chute. The bottom wall of the chute extends downwardly from the front wall and then rearwardly upwardly toward the back wall. It thus forms with the intermediate and side walls a trough portion for the chute, the trough extending below and forwardly and rearwardly of the throat.
The front wall of the chute is provided with an opening which is normally closed by a pivotally mounted door and through which a finger of a caller can be inserted to retrieve returned coins delivered to the trough. Another opening is provided at the rear of the top wall of the chute. This opening receives coins which are being returned to a caller from the payphone's coin return mechanism. After the returned coins pass through this opening they fall onto the intermediate wall of the throat and slide downward to the trough at the bottom wall for retrieval by the caller as already described.
Theft of coins from payphone coin return chutes as a result of "stuffing" the coin return chute has been a continuing problem in payphones having coin return mechanisms of the type described above. Stuffing has been a serious problem for many years. According to one method of "stuffing" a payphone, the thief inserts a compressible obstruction through the coin return door, past the opening in the front wall and trough, into the throat of the chute. The obstructing material is typically cotton or polyester wadding, paper, fabric or plastic sheeting, and it is used to prevent the coins which would otherwise be returned to the payphone user from falling through the coin return chute. After sufficient time, a sizable number of coins accumulates behind the obstructing material. The blockage is removed by the thief using various means and the coins cascade into the coin return trough, ready to be retrieved. The obstructing material can be cleared out either manually or by using implements such as a pick or hook. Some individuals ignite the foreign material so that it burns and turns to ash. This latter technique may also damage the payphone's internal mechanisms.
The payphone stuffing problem is an old one. This crimal problem has cost the phone companies enormous sums of money. The phone companies would not have normally collected the money lost to the "stuffers," because in properly working payphones the coins are returned for uncompleted calls. However, the phone companies usually have to refund the money lost to their irate customers. Furthermore, each phone company must employ personnel to investigate reports of payphones failing to return change, employ maintenance workers to examine and repair "stuffed" phones, and have accounting and payment systems in place to refund lost money to payphone users. The overall administrative cost of repairing damaged payphones and refunding lost money are quite high, and there is a substantial need for an inexpensive device which can be quickly and simply installed in an existing payphone and reliably prevents stuffing.
Early attempts at preventing the type of theft described above centered around designing the payphone coin return mechanism in such a way that it became disabled when the chute was stuffed. This type of solution is described, for example, in U.S. Pat. Nos.: 1,887,576; 1,901,944; 1,921,071; 1,921,072; and 2,004,615. Although disabling the coin return mechanism prevented the theft of coins, it also made it impossible to return coins to the caller in the event a call was not completed. Disabling the coin return mechanism was not an entirely satisfactory solution to the theft problem, since it was not feasible to return the coins to a caller immediately. The returning of money for uncompleted telephone calls would require an additional message to an operator and forwarding a check to the caller. This process is very costly and inefficient.
More recent attempts to prevent this type of theft involved designing a return chute which is more difficult to stuff. In particular, the back wall of the chute below the intermediate wall was brought forward, reducing the area of the trough available for a thief to work in when attempting to insert the stuffing material. The back wall was replaced by an opening closed by a pivoting door so that the obstructing material might pass out of the chute. These modifications, however, did not prove successful and there is still a need for a more effective way of preventing the stuffing of payphone coin return chutes.
U.S. Pat. No. 4,761,809 describes another attempt to design an "unstuffable" coin return. A tubular member having pointed teeth at its front end is inserted into the coin return door. A blade having additional sharpened teeth is attached to the lower surface of the intermediate wall of the throat. These teeth are intended to slice up obstructing material so it cannot form blockages, but actual usage of this modification reveals rather that the teeth facilitate stuffing because they catch and hold the stuffing material.
Still another attempt to design an "unstuffable" coin return device is described by the present inventors in U.S. Pat. Nos.: 4,966,325; 4,946,095; and 5,102,038. A roughly P-shaped sealing plate is attached to the back of the coin return door. When the coin return door is pushed open to allow the user to retrieve a returned coin, the sealing plate blocks the coin return chute and prevents the insertion of obstructing material. However, it has been found that if the coin return door is pushed open before the coins have passed through the return chute, the returned coins, particularly dimes, can lodge between the sealing plate and the return chute side walls causing the sealing plate to remain jammed in the return chute. As a result, the phone companies incur the costs of refunding the non-returned coins, investigating the reports of payphones failing to return change and repairing the jammed payphones.
U.S. Pat. No. 5,018,193 describes yet another attempt to inhibit the stuffing of coin return chutes by providing mechanical gating devices within the coin return mechanism. In particular, a first gate plate is attached to the inside bottom portion of the coin return door such that it extends into the coin return trough. In addition, a second gate plate hangs downward from the front edge of the bottom wall of the coin return chute such that the first and second gate plates combine to close off access to the coin return chute when the coin return door is opened. Although these gate plates are intended to permit the return of coins while preventing a thief from stuffing obstructing material into the return chute, it has been found that coins passing through the return chute tend to lodge between the side walls of the return chute and the gates, thereby jamming the door closed and preventing the payphone user from retrieving returned coins.
Another method of "stuffing" a payphone involves running a string from the payphone coin insert slot through the coin return mechanism to the coin return trough such that the thief can attach a small bag to the string and pull the bag up into the coin return chute to catch returned coins. Accordingly, a thief will drill a hole in a coin and tie a string to the coin through the hole. Then the thief will insert the coin into the payphone unit and allow the coin to pass through the coin return mechanism such that the coin drops into the coin return trough. Once the coin and attached string fall into the trough, the thief attaches a bag to the string and pulls the bag into the coin return chute to catch coins.
Finally, some thieves resort to blocking the payphone coin return chutes by bending the coin return door and jamming it into the coin return chute such that the returned coins accumulate in the coin return chute behind the return door. In addition, it has been found that vandals or frustrated thieves are able to insert explosive devices such as firecrackers, cherry-bombs or M80s into the coin return trough and cause serious damage to the payphone unit.